Method and apparatus for testing aerosol spray devices



i 1967 n. MILHOLLAND 3,298,518

METHOD AND APPARATUS FOR TESTING AEROSOL SIRAY DEVICES Filed March 29,1965 CYCLE CYCLE 2 SOUND ueHT WM REJECT V///////// JO E QO 5 TIME (0.01SECONDS) United States Patent 3,298,518 METHOD AND APPARATUS FOR TESTINGAEROSOL SPRAY DEVICES Dick E. Milholland, Racine, Wis, assignor to S. C.Johnson & Son, Inc., Racine, Wis. Filed Mar. 29, 1965, Ser. No. 443,2199 Claims. (Cl. 209-1113) This invention relates to the testing ofaerosol spray devices or spray cans, and more particularly it concerns amethod and apparatus for rapidlyand accurately testing the operativenessof individual aerosol spray cans while they proceed along an assemblyline.

In recent years, aerosol spray devices have achieved widespreadpopularity, as well as a greatly expanded field of application. As aresult of this, there has been a heavy demand for these items; and thisin turn has occasioned the development of improved and morerapidproduction techniques. There has remained one step in themanufacturing process, however, which hasbeen particularly difficult toadapt to increased production rates. This step involves the testing offinished devices for operativeness and quality of spray.

In the past, aerosol spray devices were tested by man ual actuation andvisual observationof the devices as they proceeded along a conveyor orassembly line. This was undesirable however, for prior to actuation,each individ ual spray device had to be pre-a'imed at a target so thatit would not spray against the observer. As production rates increased,the time involved in aiming the spray devices became more and more of ahindrance. In order to maintain high production rates, it ultimatelybecame necessary to divide the conveyor or assembly line into aplurality-of parallel branches with at least one observerinspectorstationed at each branch. In this way, each inspector would have moretime to aim and test the particular spray devices which passed along hisbranch.

According to my invention, it is now possible to test the operativenessand quality of aerosol spray devices or spray cans with high accuracyand with such rapidity that production rates in the order of 300 cansper minute can be accommodated with ease. Furthermore, such testing canbe carried out in fully automatic fashion and without any necessity fordividing the conveyor or assembly line into several branches. In fact,only a minimum of alteration is necessary to conventional assemblylines.

These unique results are achieved, according to my invention by actuallyeliminating the need for orienting or aiming the individual spray cansprior to their actuation; and further, by eliminating the need for anyvisual observation of the spray discharge from the aerosol'devices.

Essentially, my invention consists in the recognition and application ofthe fact that an aerosol spray device, or spray can, when actuated,produces a sonic disturbance whose frequency and amplitude are functionsof the intensity and degree of fineness of the spray. This sonicdisturbance, moreover, is omnidirectional and thus is substantiallycompletely independent of the direction in which the spraycan is facingat the time of its actuation.

I practice my invention by actuating individual spray cans in thepresence of a sonic detector tuned to afrequency range which correspondsto the range of sonic frequencies produced by operative spray cans whenthey are producing an acceptable quality of spray. The cans are actuatedautomatically. This is accomplished by providing a wheel so positionedon the assembly line that the cans traveling down the line will passunder the wheel in succession. As each can passes under the wheel itsvalve top is pressed down by the wheel to actuate its spray mechanism.If the spray mechanism functions properly, an acceptable sonic signalwill be generated. This signal is sensed by the sonic detector whichacts to permit the Patented Jan. 17, 1967 can to proceed down theassembly line. If, however, the spray mechanism functions improperly, ornot at all, then a proper sonic signal will not be produced and thesonic detector will operate to actuate a reject mechanism for flivertingthe unacceptable spray can from the assembly In a particularapplication, to be described in detail hereinafter, I provide a spraycan detecting device, such as a photosensitive cell located in theassembly line slightly beyond the'actuating wheel. This spray candetecting device is arranged to operate a reject mechanism each time itdetects the presence of a can. The reject mechanism, when actuatedoperates to remove the detected can from the assembly line. The sonicdetector is arranged such that when it detects the occurrence of anacceptable spray, it operates to disconnect the can detector from thereject mechanism. Thus, when' an acceptable spray can passes along theassembly line, the sonic signal generated by the actuation of its spraymechanism will cause the sonic detector to disengage the rejectmechanism so that when the presence of the can is detected immediatelythereafter the reject mechanism will not operate and the can willproceed down the line. If, on the other hand, the spray mechanism isunacceptable, no output will be produced by the sonic detector and thecan detector will remain effective to operate the reject mechanism forremoving the can from the line.

There has thus been outlined rather broadly the more important featuresof the invention in order that the detailed description thereof thatfollows maybe better understood, and in order that the presentcontribution to the art may be better appreciated. There are, of course,additional features of the invention that will be described hereinafterand which will form the subject of the claims appended hereto. Thoseskilled in the art will appreciate that the conception upon which thisdisclosure is based may readily be utilized as a basis for the designingof other structures for carrying out the several purposes of theinvention. It is important, therefore, that the claims be regarded asincluding such equivalent constructions as do not depart from the spiritand scope of the invention.

A certain embodiment of the invention has been chosen for purposes ofillustration and description, and is shown in the accompanying drawing,forming a part of the specification, wherein:

FIG. 1 is a schematic representation of a system used in practicing thepresent invention; and

FIG. 2 is a timing diagram useful in considering the operation of thesystem of FIG. 1.

In FIG. 1, a portion of an assembly line 10 is shown with a series ofcompleted aerosol containers or spray cans 12 moving therealong in thedirection of an arrow 14. The containers 12 are positioned upright on amoving belt 16 and are guided between rails 18 which extend along theassembly line on each side thereof.

The aerosol containers 12 are each provided with a depressible actuatorbutton 20 at the top thereof. The

actuator buttons themselves have nozzle openings 22 through whichaerosol mist or spray passes when the buttons are depressed. It will benoted that while the containers 12 themselves are aligned in uprightposition on the belt 16, their actuator buttons 20 are randomly orientedso that the nozzle openings 22 will direct spray in different directionsfrom one container to the next.

There are provided a testing station 24 and a reject station 26 in closepositional relationship along the assembly line 10. The testing station24 includes a cam wheel 28 mounted by means of an arm 30 centrally abovethe belt 16 with its axis transverse to the belt so that as each aerosolcontainer passes under the Wheel 28, the actuator button 20 at the topof the container becomes depressed by the wheel. Thus, as each containerpasses under the wheel it becomes actuated thereby for a short period oftime.

Immediately adjacent the cam wheel 28 there is provided a soundtransducer, such as a microphone 32, mounted on an arm 34. Themicrophone 32 is connected to a first amplifier 36; and in conjunctionwith the amplifier it produces electrical signal representative of thehose 38 which is connected to a source of high pressure air (not shown).The air hose 38 terminates at a nozzle 40 which is positioned to directblasts of high pressure air across the belt 16 toward the space 37. Thusany container on the belt and in alignment with the space 37 will beblown off the belt and into the space upon a blast of air from thenozzle 40.

An air valve 42 is interposed along the hose 38 to control the blasts ofair through the nozzle 40. The air valve 42 is actuated to allow a blastof air out through the nozzle by means of an electrical solenoid 44,which in turn is arranged in an electrical circuit to be described morefully hereinafter.

There is also provided at the reject station 26 a photoelectricdetection arrangement comprising a light source 46 on one side of thebelt 16 and a photoelectric detector 48 on the opposite side of thebelt. Whenever a container 12 passes through the reject station itinterrupts light from the source 46 and thus casts a shadow on thephotoelectric detector 48. The photoelectric detector in turn respondsto this shadow by producing an electrical output signal.

The various components described above are interconnected by means of anelectrical circuit arrangement. This arrangement includes a first relay50 connected to be energized by the output of the first amplifier 36.Thus, Whenever a properly operating spray container 12 passes under andis actuated by the wheel 28, the sounds which accompany the emission ofspray therefrom are detected in the microphone 32 and converted intoelectrical signals which are amplified in the amplifier 36 and used toenergize the first relay 50. The first relay 50, when energized,operates a movable arm 52 of a single-poledouble-throw switcharrangement. The movable arm 52 is connected to the output of a secondamplifier 54 which receives output signals from the photoelectricdetector 48. Thus whenever the photoelectric detector 48 producessignals as a results of the passage of a container 12 through the rejectstation 26, the movable switch arm 52 receives a finite voltage from thesecond amplifier 55.

The movable switch arm 52 of the first relay 50 is normally in contactwith a first stationary terminal 56 connected to a second relay 58; butis movable away from that terminal during energization of the firstrelay 50 to contact a second stationary terminal 60 connected to theenergization circuit of the first relay.

The second relay 58, when energized, closes a pair of normally openswitch contacts 62 to connect a voltage source 64 in closed circuit withthe solenoid 44 which actuates the air valve 40.

During operation of the system, each aerosol container 12 on theassembly line is moved along under the cam wheel 28 by the moving belt16 so that its depressible actuator button is pressed downwardly by thewhee-l. If the container sprays properly it will emit a certain soundwhich is detected by the microphone 32 and amplified in the firstamplifier 36 whose output in turn causes energization of the first relay50. The relay 50 in turn moves its switch arm 52 so that it becomesdisconnected from the first stationary contact 56 and becomes connectedto the second stationary contact 60. As a result of this, the circuitconnection to the second relay 58 is broken and it is thus incapable ofclosing the contacts 62 to actuate the air valve solenoid 42.Accordingly, the container 12, whose spray mechanism was operatingproperly, is not blown off the belt 16. If, on the other hand, no sprayor an improper spray was produced as the container 12 passes under thecam wheel 28, the microphone 32 and amplifier 36 do not produce anysignal to energize the first relay 50. Consequently, the circuitconnection between the second amplifier 55 and the second relay 58remains intact so that when the improperly operating container passesthrough the reject zone 26, the signal produced by the photoelectricdetector 48 in response to the shadow cast thereon by the improperlyfunctioning container, will cause the second amplifier 55 to produce anoutput which energizes the second relay 58. This in turn closes thecontacts 62 placing the valve actuating solenoid 44 in circuit with thevoltage source 64 to operate the air valve 42 and cause a blast of airfrom the nozzle to blow the improperly functioning container off thebelt 16.

Because of the high speed at which the containers 12 proceed alongthrough the testing and reject stations 24 and 26, these stations mustbe displaced by a finite amount along the assembly line, or the rejectmechanism would be incapable of operating swiftly enough to reject animproperly functioning container. On the other hand, the displacement ofthe belt and reject stations presents certain other problems. Forexample, since it is the passage of a properly functioning containerthrough the test station which deactivates the reject mechanism, if thestations are too widely separated, a properly functioning container 12will have passed completely through the test station by the time itreaches the reject station so that the test station would no longer beoperative to deactivate the reject mechanism.

The arrangement of the present invention overcomes the above difiicultyin a very reliable manner. According to this arrangement, the test andreject stations 24 and 26 are spaced closely enough so that a smallamount of overlap in the timing of their respective operations occurs asa container passes through them. Also the circuit arrangement is suchthat this overlap is effective to cause the output of the secondamplifier 54 at the reject station to actually maintain the rejectmechanism in a deactivated condition if the first relay 50 had been inoperation during the overlap period.

The timing diagram of FIG. 2 is useful in visualizing the cooperativeinteraction of the test and reject stations 24 and 26 to preventinadvertent rejection of properly operating containers. Cycle 1 of FIG.2 illustrates the timing for the case where a properly operatingcontainer has passed through the two stations 24 and 26. As thecontainer passes through the test station 24 its spray top becomesactuated by the cam wheel 28 and a spray and an accompanying sound areproduced beginning at a time T=O. This spray and its accompanying soundcontinues while the containers pass under the wheel 28; and it lasts forabout 0.02 second. During this time, the first relay 50 is energized andits movable switch arm 52 is maintained down against the lower or secondstationary contact 20. Prior to the expiration of the 0.02. secondinterval (at approximately T=0.0l), the con tainer 12 enters into thereject station 26 and begins to interrupt the light beam so as to cast ashadow on the photoelectric detector 48 which in turn causes the secondamplifier 55 to produce a finite output voltage. This light" controlledoutput voltage lasts for about 0.04 second (from T=0.01 to T=0.05). Thevoltage output from the second amplifier 54 is applied to the movableswitch arm 52 of the first relay 50; and because this arm is connectedvia the second stationary contact 60 to the energization circuit of thefirst relay 50, the output voltage of the second amplifier 54 willmaintain the first relay 50 in its energized state even after the firstamplifier 36 ceases to produce its relay energizing output.Consequently, the second relay 58 will not operate at all during thepassage of the container 12 through the reject station 26 even thoughthis station is separated from and not continuously acted on by outputsfrom the test station 24.

Cycle 2 of FIG. 2 illustrates the timing arrangement for the situationwhere an inoperative container passes through the test and rejectstations. Since the inoperative container will not produce an acceptablesonic output, no sound signal is produced in its passage through thetest station 24. Thus, the first relay 50 remains unenergized and itsmovable switch arm 52 is maintained in contact with the first stationarycontact 56 and in circuit with the second relay 58. As the inoperativecontainer passes into the reject station 26, it interrupts the beam fromthe light source 46 and casts a shadow on the photoelectric detector 48which in turn causes the second amplifier 54 to produce an output which,by virtue of the position of the movable terminal 52, causesenergization of the second relay 58. This relay in turn closes thenormally open switch 62 to place the solenoid 44 into circuit with thevoltage source 64. The air valve 42 then operates to allow a blast ofair to blow the inoperative container ofi" the belt 16 and out throughthe space 37.

Having thus described my invention with particular reference to thepreferred form thereof, it will be obvious to those skilled in the artto which the invention pertains, after understanding my invention, thatvarious changes and modifications may be made therein without departingfrom the spirit and scope of my invention, as defined by the claimsappended thereto.

What is claimed as new and desired to be secured by Letters Patent is:

1. A method for testing the operativeness of aerosol spray devices,comprising the steps of conveying a series of such aerosol spray devicesin succession along a given path, actuating each spray device during itspassage through a given region of said path, monitoring the soundproduced by each spray device during its passage through said givenregion and removing spray devices from said given path upon theirfailure to produce a sound commensurate with a given acceptable sprayoutput during actuation.

2. A method for testing aerosol spray devices as they pass along aconveyor line and selectively rejecting inoperative devices, said methodcomprising the steps of actuating each spray device as it passes througha first given region along said line, producing a first electricalsignal during the occurrence of sounds which accompany the emission of aproper spray from each aerosol spray device, producing a secondelectrical signal during the passage of each spray device through asecond region subsequent to said first given region along said conveyorline and operating a reject mechanism to remove from said conveyor lineeach spray device upon its causing the production of a second signalonly when such container has failed to cause the production of a firstsignal.

3. An aerosol spray testing device comprising, means for moving aerosolspray devices in succession along a given path, an aerosol spray deviceactuating means arranged along said path at a given point to cause briefactuation of each spray device passing thereby, a micro phone positionedin the vicinity of said actuating means and connected to produce firstsignals in response to sounds which accompany the actuation of eachproperly operating spray device, a spray device detection circuitconnected to produce second signals upon the passage of spray devicesthrough said actuating means, and a signal coincidence detector circuitconnected to produce a reject signal upon the absence of a first signalduring the occurrence of a second signal.

' tion circuit connected to produce second signals upon the passage ofspray devices through said actuating means, and a signal coincidencedetector circuit connected to produce a reject signal upon the absenceof a first signal during the occurrence of a second signal.

5. In an.assembly line along which aerosol spray devices, actuable bydepression of their tops, move in upright orientation in rapidsuccession, the combination of a wheel mounted above said assembly linewith its peripheral surface moveable down against and along with thetops of spray devices passing thereunder for automatic brief actuationof same, a microphone positioned in the vicinity of said cam element andconnected to produce first signals in response to sounds which accompanythe actuation of each properly operating spray device, a spray devicedetection circuit connected to produce second signals upon the passageof spray devices through said actuating means, and a signal coincidencedetector circuit connected to produce a reject signal upon the absenceof a first signal during the occurrence of a second signal.

6. Apparatus for testing valves through which fluids pass at highvelocity, said apparatus comprising a valve actuating means arranged toproduce brief actuation of a valve to be tested, a sound detector turnedto produce output signals in response to the occurrence of audible disturbances which accompany the actuation of a properly functioning valve,and means mounting said sound detector in proximity to said valveactuating means.

7. Apparatus for testing the operability of aerosol spray devices whichpass a given point along a conveyor line in rapid succession, saidapparatus comprising an aerosol spray device actuating means arranged atsaid given point to cause brief actuation of each spray device passingthereby, a microphone positioned in the vicinity of said actuating meansand connected to produce first signals in response to sounds whichaccompany the actuation of each properly operating spray device, a lightsource and a photoelectric detector arranged with a mutual line of sightwhich intercepts said path at said given point such that the passage ofaerosol devices thereby produces second signals, and a signalcoincidence detector circuit connected to produce a reject signal uponthe absence of a first signal during the occurrence of a second signal.

8. An aerosol spray testing device comprising means for moving aerosolspray devices in succession along a given path, an aerosol spray deviceactuating means arranged along said path at a given point to cause briefactuation of each spray device passing thereby, a microphone positionedin the vicinity of said actuating means and connected to produce firstsignals in response to sounds which accompany the actuation of eachproperly operating spray device, a spray device detection circuitconnected to produce second signals upon the passage of spray devicesthrough said actuating means, and a signal coincidence detector circuitconnected to produce a reject signal upon the absence of a first signalduring the occurrence of a second signal, and a reject mechanismoperable to divert aerosol spray devices from said conveyor line uponreception of reject signals from said signal coincidence detectorcircuit, said reject mechanism being located along said path immediatelybeyond said actuating means to eliminate each non-operable spray device7 while it passes through a first given region along said line, sonicdetection means arranged to produce a first signal during the occurrenceof sounds which accompany the actuation of a properly operating spraydevice in said first given region, spray device detection means arrangedto produce a second signal during the passage of an aerosol spray devicethrough a second given region which overlaps said first given region,reject means located in said second given region and operative to removea spray device passing thereby from said line, double throw switch meansand switch actuating means, said double throw switch means beingarranged to switch between a first normal condition directing saidsecond signal to said reject means for operating same and a secondactuated condition directing said second signal to said switch actuatingmeans for op- UNITED STATES PATENTS 1,881,543 10/1932 Hartig et al.

2,635,746 4/19 53 Gordon 2091 1 1.9 2,698,929 1/1955 Greachen et al.340239 2,999,589 9/1961 Norwich 209-1119 X 3,028,450 4/1962 Manning7340.5 X

ROBERT B. REEVES, Primary Examiner.

1. A METHOD FOR TESTING THE OPERATIVENESS OF AEROSOL SPRAY DEVICES,COMPRISING THE STEPS OF CONVEYING A SERIES OF SUCH AEROSOL SPRAY DEVICESIN SUCCESSION ALONG A GIVEN PATH, ACTUATING EACH SPRAY DEVICE DURING ITSPASSAGE THROUGH A GIVEN REGION OF SAID PATH, MONITORING THE SOUNDPRODUCED BY EACH SPRAY DEVICE DURING ITS PASSAGE THROUGH SAID GIVENREGION AND REMOVING SPRAY DEVICES FROM SAID GIVEN PATH UPON THEIRFAILURE TO PRODUCE A SOUND COMMENSURATE WITH A GIVEN ACCEPTABLE SPRAYOUTPUT DURING ACTUATION.